Hydraulic jack



Oct. 7 19% 1,510,4@2

J. B. DELL HYDRAULIC JACK Filed ADIil 22 1920 @7530022 B. DELL, INPENTGR.

TTORNEX Patented Uct. 7, 1924.

@At-leiter JACOB B. DELL, OF ALTOONA, PENNSYLVANIA.

HYDRAULIC JACK.

Application led Ap1'i122, 1920. Serial No. 375,859.

le all whom t may concern.-

Be it known that l, ,lecon B. DELL, .a of vthe United States oi America, .ding at Altoona, in the county 0i Blair State :of Pennsylvania, have invented certain new and ,useful 'Improvements in Hydraulic Jacks, of which the following is speeiiieation.

The present invention relates .to hydraulic jacks and has as a special feature automatic Y u 1ean-S for releasing the internal fluid pressure, and lifting power of the jack when the load reaches `a predetermined amount, set as l.the allowable lifting capacity of the particualar jack, and thus prevent the bursting .of the jack parts by making them perform :an overload duty.

lSpecial-ly devised means is also provided in iny invention for releasing the lifting jack from its load after its full extension point has been reached, by merely continuously operating the ordinary hand lever used in .extending the jack under a load. The .release ot the jack in this instance is accomplished in 4a gradual manner, and is under .the control .of Vthe voperator, all of which is explained more fully hereinafter in this specification.

In the accompanying drawings forming part ofathis .specification l have lshown one complete .embodiment of my invention, constructed according to the best mode l have so far devisedior the practical ,application O f the principles of my invention. i

In the drawings Figure 1 is a vertical .cenltral section of my improved hydraulic )ac Figure 2 is a horizontal section on line 2.*2 of Figure 1. Y

Figure .3 is a horizontal section on line 3f?) 0f Fig. l.

Figure 4 Ais a horizontal section on line of Fig. l.

Figure V5 is a horizontal section on line 5&5 lg. l..

The numeral 1 indicates a hydraulic or duid-pressure actuated jack, having the usual hollow cast metal head 2, an outer cylinder or shell 3, a ram 4, and a pist-on 5. The head 2 is fof ,the .ordinary :type and is `screwthled-ded at 6 on the upper `end of the .ram 4, and the latter slidably operates within .the .cylinder :3 in the usual manner. 'The outer eylinder in the jack shown is formed at its ibase into outwardly projecting flanges 7 and v.saidcylinder isehown with the walls 8 and reciprocates within same. head `21Vhas a passage 22 connecting the formed integral with the bottom `9, but any of the usual types `of cylinders or bases may be used. Theram l is cylindrical in shape, Vand the lower endet same is provided with a screw-thread 10 in which the pump 11 is screwed into engagement therewith. A The pump 11V comp-rises the following parts. 12 indicates a preferably lsteel casting of circular cross-section and having an outstanding annular flange 13 formed thereon. Seated in the lower or recessed end 14. of casting 12 is the :annular leather packing 15 of section shown in Figure 1, and secured in place by the packing ring 16, which last .is screw-threaded at 17 on the end of the casting 12.

The ram reciprocates in the cylinder 3 vwhen properly actuated, and it is evident that no fluid can pass from expansion chamber 18 beneath the pump 11 to the fluid res ervoir 19 by means of any space between the periphery of the Piange 13, and the inner Wall of `the cylinder 3 at 2O on account of the ,tight non-leaking it of .the leather packing ring 15 against said inner wall. The

`casting 12 is formed into a chamber 24, into which the piston v5, and its head 21 projects, The piston passage 23 in a transverse horizontal direction with the chamber 24. A valve stem 25 -reciprocates in the chamber or passage 23, and said stem `terminates vin a valve head 26. which coacts `with the valve seat 27. ablesmall lead passages 2S, 28 lead from the small Achamber 29 to the portion .of the chamber 211 indicated by numeral 30 below the piston head.

lt is seen that when piston 5 is raised that the valve head 26 remains in the position shown resting on the bottom of the small chamber 29, and that when the 'piston is operated in a downward direction that the valve head 26 engages the seat 27 and closes fthe valve. 31 indicates leather packing, which is secured in place by the nut 32 screw-threaded on the end of the piston 5.

From point 30 a passage 33 leads downward enclosing the V.valve stem 3l, the latter terminating in a valve head 35. The valve `stem is fluted or grooved at 36, 36 to enable iuid to reach the valve head 35, and chamber 37 when the valve head is in an open position. 89 is a spring'which tends to hold the valve head '35 `on its seat 39 and keeps the valve closed. Beneath the spring 38 is a nut Suit- 40 screwed into the end of the casting 12 to form an abutment for the spring 38, and a passage 41 leads through the nut to the chamber 18 as shown. From the above description it is seen that when the piston reciprocates fluid in chamberV 19 is pumped by pump 11 into the chamber 18, and ordinarily the casting 12 will rise in the cylinder 3, and lift any load placed on the top of the head of the ack 2, as is at once understood. 0n. the piston stem is an adjustable collar 42 which is fixed in position on said stem or piston 5 by means ot' a set-screw 43, the use or which collar 42 will be explained hereinafter in this specication. The above teatures are of ordinary construction, and the feature of my invention involving the safety release mechanism will now be described.. Same consistsV in a passage 44, leading from the passage 33, thelatter being plugged by a screw 45 as shown. From passage 44 leads a Vpassage 46 which widens into passage 47, in which last the valve stem 48 reciprocates The valve stem 48 is iuted or grooved at 49 so that fluid can pass from chamber 47 to chamber 50 when the valve 51 is open, as is readily understood. 52 lindicates a spring which tends to keep the valve 51 in a closed position, and two washers having apertures therethrough and num-V 'bered 53, 53 are used as abutting elements at the ends of the spring 52. A nut 54,. and a lock nut 55 retain the spring and adjacent parts in position in the casting 12. A passage 56 connects chamber 19 with chamber 50. lFrom this description of the safety release mechanism it is seen that as soon as the pressure in the chamber 33 reaches a certain predetermined point equivalent to the strength ot spring 52 used in the particular jack under consideration, that such pressure will overcome the spring 52 and open the valve 51 and release the iiuid in the passages` The load releasing mechanism will now vbe described, and Vconsists -ot the following c parts. Leading from the reservoir 19 .is a passage 57, in which are located the slidable parts 58, 59, and 60 the latter being the stem ot the valve 61. The valve stem 6() and the 1 )art 59' both have iuted stems at 62 for the `passage ot fluid therealong when the valve 61 is open. The part 58 has a cut-away por- Y tion at 63, into which a screw-threaded plug (54 engages forming a securing means to hold part 58 in the casting 12. It is seen further thatfthe part 58 can reciprocate within the limitso'f the cut-away portion 63 for apurpose below described. The valve 61 operates against spring 65 in the chamber 66, and

said spring in turn bears against the nut 67, which last is screwed into engagement with Y the base of the casting 12.

A passage 68 is formed in the nut 67 to provide a means of communicationbetween chamber 18, through the valve 61 when same is open, through the iluted partV 60, and passage 69and by means of the peripheral recess 70 into the reservoir 19. The piston 5 is reciprocated by meansof the lever 71 in the usual mannerV by means of the axle 72, and Lshort lever 73, working about pointl 74 as a ulcrum. `After the ram 4 carrying the` head 2 has been eX-' tended by pumping fluid from chamber 19 into expansion chamber 18 by means of the pump 11, as high as it is desired to elevate the'load on the head 2, it is evident that` by reversing the position of the lever-71 :in its socket 77, so that'the projection 75 on same is reversed ,to position; 76, it is seen that in this Acase thedownward travel Yof the pistonwill continue yuntil -therbot- '58, and 59, unseat the valve 61 thereby vadmitting fluid from the expansion cham-` ber 18, byrmeans Aot the passages 69, and 7 O into .the reservoir 19. vThis action-if` persistcd in by turth'eroperationot the lever 1, will lower the ram 4to its lowest position as shown inthe drawings in Figure 1.

The purpose ot' plug 64, and the cut-away 100 portion or slot 63 formed inthe part 58, isV

to prevent the latter from falling into fluid reservoir 19 under certain-conditions in service. It is evident that when the jack is handled in use, it maybe placed in an inverted position, while the piston 5 -is in extendedposition, Vin which lease the collai Llf2-being ino-longerV 1n Vproxima-te position Vwith respect to the part 58, the latter' would leave passage 57, and loe-deposited in reservoir 19, if it were not for the action of the plug G4 against'the end ofi the slot 63. The load releasing mechanism, is very use ul in thatV the same lever whichF raises the load, need simply be reversed in position in U5 i its socket 77, in order `to start the load releasing mechanism, and lower the ram Vin the cylinder 3. Moreover the loadV releasing mechanism is positive in operation in" luy-invention, and not subject to the uncertainties of small screw devices often used on hydraulic jacks for the purpose of releasing the jack-from the load.

y Attention is'directed to the VutilityV of having the Vcollar 42`adjustably mountedon 129 the stem of the piston 5, so that the operation of the parts 58, 59,v and 6() ican be adjustably controlled according to the physical conditions which `obtain `without the jack, to waz-the rei-.Irion orare .bottom `edge '130 of the lever 7l and the rigid lug 78, before described. It is also seen that the length of the groove 63 and the relative position of the adjustable collar 42 on the stem of piston 5, determine Ithe limit of movement of the parts 58, 59 and 60, as well as the valve 61 as is at once understood.

I claim:

1. In a hydraulic jack provided with a fluid reservoir, a pumlp and expansion chamber, a pump piston having a stem, means for expeditiously lowering the jack comprising a pump casting having a peripheral recess, a valve passage connecting the expansion chamber with the latter, a normally closed valve having a stem in the valve passage, adjustable means on the pump piston stem for depressing said valve, means carried in the pump casting for transmitting motion from the depressing means to the valve stem, and means for preventing dislodgment from, and limiting the travel of said transmitting means within the pump casting.

2. In a hydraulic jack provided with a fluid reservoir, a pump and expansion chamber, a pump piston having a stem, means for expeditiously lowering the jack comprising a pump casting having a peripheral recess formed thereon, a valve passage connecting the expansion chamber and the fluid reservoir, a passage connecting the valve passage and the peripheral recess, an upper slidable member, an intermediate slidable member and a normally closed valve having a stem located in said valve passage, a slot formed in the side of the upper slidable member, a plug carried by the pump casting in engagement with the said slot for preventing dislodgment, and limiting the travel of said slidable members, and adjustable means on the piston stem adapted to engage the upper slidable member for operating the aforesaid valve.

'3. In a hydraulic jack, a safety pressure means comprising a fluid reservoir, a pump having a piston and a piston chamber, a jack expansion chamber, a passage connecting the two last named chambers, a normally closed valve in said passage, a second passage connecting the irst passage with the fluid reservoir, a normally closed valve in the second passage adapted to automatically open when the pressure in the eXpansion chamber reaches a predetermined point; in combination with means for eXpeditiously lowering the jack consisting of a. pump casting having a peripheral recess formed thereon, a valve passage connecting the expansion chamber and the pump casting peripheral recess, anormally losed valve in the valve passage, a fluted stem on the valve head, adjustable means mounted on the pump #piston stem for depressing said last named valve, and means for transmitting' motion from said depressing means to the fluted valve stem.

4. In a hydraulic jack, a safety pressure means comprising a fluid reservoir, a pump having a piston and a piston chamber, a jack expansion chamber, a passage connecting the two lastk named chambers, a normally closed valve in said passage, a second passage connecting the iirst passage with the fluid reservoir, a normally closed valve in the second passage adapted to automatically open when the pressure in the expansion chamber reaches a predetermined point; in combination withmeans for eX- peditiously lowering the jack consisting of an adjustable collar on the stem of the above-named piston, a pump casting having a peripheral recess formed thereon, a valve passage connecting the expansion chamber and the pump casting peripheral recess, a normally closed valve in the valve passage, a fluted stem on the valve head, and means for transmitting motion from the piston collar to the flute-d valve stem for the purpose of permitting fluid to pass from the expansion chamber to the fluid reservoir.

5. In a hydraulic jack, a safety pressure means comprising a fluid reservoir, a pump having a piston and piston chamber, a jack expansion chamber, a passage connecting the two last named chambers, a normally closed valve in said passage, and means for relieving the pressure in the expansion chamber when same reaches a predetermined point; in combination with means for expeditiously lowering the jack consisting of an adjustable collar on the piston stem, a pump casting having a peripheral recess formed thereon, a valve passage connecting the expansion chamber and 'the pump casting peripheral recess, a normally closed valve in the valve passage, a liuted stem on the valve head, means for transmitting motion from the piston collar to the fluted valve stem, and means for limiting the movement of the said transmitting means.

In testimony whereof I aflix my signature.

JACOB B. DELL. Witnesses VILLIAM A.. HIRTLE, MARY A. JUNKIN. 

